How are leakage currents measured?

Involves the following devices: SECUTEST SII+ / SIII+

For technical reasons, leakage current measurement in the IT network can only be carried out using the substitute device leakage current measurement. When measuring using the residual current method or the direct leakage current measurement, you will usually only measure currents of a few μA due to the galvanic isolation of the supply.

The great advantage of the IT network is that any leakage currents that occur do not lead to any danger because the current cannot flow.

The substitute leakage current measurement does not require a connection to the protective conductor for testing, since the test voltage and the protective conductor are generated galvanically separated from the supply network. The test instrument forms its own TN network, so to speak. Therefore, this method is the best method for leakage current measurement in IT networks.

The disadvantage is that the substitute device leakage current measurement does not work with electronically switched DUTs, because the load capacity of the test voltage is usually not sufficient to put a load into operation. Such DUTs can only be tested in a TT or TN network.